A low-cost, low-technology way of sequestering atmospheric carbon on a global scale with the tools we are already using.
Depending on how you classify it, rangelands (land used for grazing animals) cover 40-70% of earth's land surface and represent the largest ecosystem under human management. Recent research has shown that these lands can sequester in excess of 10 tonnes per hectare of carbon annually. Moreover, when carbon is returned to the soil (most soils have lost 50-70% of their carbon in the last 200 years) it increases water-holding capacity and primary production, meaning that it increases the food supply and provides resilience against both drought and flooding in a changing climate. While the particular practices necessary to increase carbon sequestration will necessarily vary by locality and practitioner, the underlying ecological processes are universal.
While the research on row-crop agriculture's ability to sequester carbon is ongoing, preliminary results suggest that it is highly possible to increase soil carbon while also growing fruits and vegetables.
What actions do you propose?
There are a suite of practices which can be undertaken on grasslands which seem to increase carbon sequestration. Among these are compost application, planned rotational grazing, keyline plowing, silvopasture, and, riparian restoration. There is ongoing research on these and other practices to determine which practices are most effective at sequestering carbon.
In a row-crop setting the practices which seem to sequester carbon include: no-till, organic, agroforestry, covercropping, perennials, permacutlure, and, biodynamic. There seems to be far less research on the ability of these different systems to sequester carbon, but it is beginning to be taken more seriously.
We know that many of these practices, and others, sequester carbon for decades or centuries. We have the land, the managers and the equipment. What we are largely lacking is the know-how by the producers and the incentive.
Therefore, this proposal is to train farmers and ranchers to manage their land for climate benefits while simultaneously educating consumers of the benefits of well-managed agricultural land. This education piece is crucial for consumers that understand what they are really supporting with their purchases are often willing to pay more for a more responsible product, thus creating the incentive for the farmers to manage in a more ecologically responsible manner.
Who will take these actions?
Ultimately, it will be the farmers that undertake the climate beneficial actions. However, the training of the farmers and the education of the consumers will be performed by the thousands of nonprofits world-wide who work in both rural and urban communities on food, agriculture, health and climate. Countries with functional and responsible governments can also be expected to promote this work.
Where will these actions be taken?
This work can be undertaken globally. However, places such as the Amazon Rain Forest are more climate beneficial left intact. Therefore, carbon sequestration on agricultural lands is really only beneficial when it does not include conversion from native forests. This work really takes place on the land which is already being intensively managed for food production. That said, their are huge negative consequences of converting agricultural land to urban/suburban purposes, therefore, there should be corresponding benefits to converting urban spaces to agriculture.
How much will emissions be reduced or sequestered vs. business as usual levels?
If we take the lower number of 40% of earth's surface we come up approximately six-billion hectares of rangeland on earth. If we could sequester even 10% of the 10 tonne potential on every hectare, we would sequester six-billion tonnes (or 6 gigatons) of carbon per year with these practices. This would more than offset global emissions from the entire transport sector. If we could sequester the same amount of carbon on our approximately 2.5 billion hectares of cropland, we could further offset all the emissions from our waste and wastewater sector. None of this takes into account all of the avoided emissions inherent in the composting process (such as the 3 gigatons of avoided emissions from composting per ton of finished product), or from grain production as more animals are moved to pasture-based production.
What are other key benefits?
Beyond the sizable climate benefits, there is also the decrease in flooding, increase in drought resistance, more food produced that is healthier, more income for the farmers, healthier and more biodiverse ecosystems, and, more beautiful landscapes.
What are the proposal’s costs?
It is impossible to estimate the potential cost of this project as it is dependent on the costs of employing experts in each locality, the aptitude of farmers to change their practices, and, how much consumers are willing to incentivize this type of farming.
There are not any ecologically negative side effects to better management of agricultural lands.
All of the education and training would take place in the short-term, as the practices and technologies needed for this are already broadly available. The resulting sequestration will take place in the medium term as the land takes some time to respond to better management. In the long term a decrease in atmospheric ghg concentrations would be expected.